Intracrystalline alkylation of benzoate ions into layered double hydroxides

Several layered double hydroxides (LDHs) containing metals of different nature intercalated with benzoate anions have been synthesised in order to study the O-alkylation reaction of the interlayered species with alkyl halide in dry media conditions. In all the cases, the expected ester was obtained with good yield (> 60%). The presence of anionic benzoate in the structure was prefered to obtain high selectivity and yield, in comparison with the use of sodium benzoate supported as a salt. The use of MW irradiation to promote these reactions has permitted the reaction time to be reduced considerably. The influence of water present in the LDH on the ester formation has also been investigated. Characterisation of the LDH support before and after reaction is also presented, showing the influence of the nature of the cations located in the octahedral sheets. The support can be regenerated, with no effect on the reactivity.